The present invention relates to a motor driven screwdriver.
More particularly, it relates to a motor driven screwdriver with a planetary transmission arranged between a driving shaft and a driven shaft and a measuring value transducer for determining a drive torque transmitted by a drive train.
Motor driven screwdrivers of the above mentioned general type are known in the art. One of such motor driven screwdrivers is disclosed for example in the German document DE 32 14 889. The measuring value transducer has a torsion shaft which is connected through an end toothing with a carrier sleeve of a planetary transmission on the one hand and is connected with a driven shaft on the other hand and not supported separately. Due to the unavoidable play in the toothings the measuring accuracy of the measuring value transducer is affected. In another embodiment the measuring value transducer is formed as a separate structural group with its own housing and supported inside the housing. Such a construction increases the measuring accuracy, however, it is connected with relatively great number of parts and also requires a great mounting space.